Calling line identification



Nov. 3o, 1954 A. E. JQEI.; JR ssn-.,928

A Y CALLING LINE IDENTIFICATION Filed July 14, 1951 15 Sheefls-Sheet l ATTORNE V Nov. 30, 1954 A. E. JOEL, .IR

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CALLING LINE IDENTIFICATION Filed July 14, 1951 15 Sheets-Sheet 7 /N VE N TOR By A E. JOEL, JR

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A77' ORNE V Nov. 30, 1954 A. E. JOEL, JR

CALLING LINE IDENTIFICATION 15 Sheets-Sheet lO Filed July 14, 1951 QMS ATTORNEY.

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CALLING LINE IDENTIFICATION Filed July 14, 1951 15 Sheets-Sheet 12 ATTORNEY Nov. 30, 1954 A. E. Joel., JR 2,695,928

CALLING LINE: IDENTIFICATION Filed July 14. 1951 15 Sheets-Sheet 13 /NVENTOR Q By Af. JOEL, JR. C'. 220,222;

ATTORNEY Nov. 30, 1954 A, E, JOEL, JR 2,695,928

CALLING LINE IDENTFICATION Filed July 14, 1951 l5 Sheets-Sheet 14 /N VENT OR ,4.5. Joe-,Jm

ATTORNEY Nov. 30, 1954 A. E. JOEL, JR

CALLING LINE IDENTIFICATION Filed July 14. 1951 15 Sheets-Sheet l5 RL mm h @uw WE AC B il. @um

ATT ORNE V United States Patent() CALLING LINE IDENTIFICATION Amos E. Joel, Jr., .South Orange, N. J., assgnor `to Bell Telephone Laboratories, Incorporated, 'New York, N. Y., :1i-corporation ofNew York Application July v114, 1951, Serial No. 236,717

12 Claims. (Cl. 179-18) This invention relates to dial telephone systems .and has for its object .to facilitate :the .identification of calling lines Afor charging purposes.

In the cross-bar dial system, lines are assigned to the switch terminals without regard to their designation, but the sleeve conductors of such/lines are cross-connected to terminals on lan auxiliary frame, known as a number group frame, which are individual to the designation, these terminals being used =by the `common control .equipment to test whether the line is busy l,or idle.

My yPatent No. 2,490,441, granted December .6, 1949, is directed to means for using the number group frame to identify a .calling line 'for chang-ing purposes. ln that patent, the sender Apicksan idle identifier :and special means is provided by which-the selected .identifier may :determine the number group in which the calling line appears.

`In :accordance with the present invention, any one of a plurality of senders `starts :allot :a plurality `of identiers simultaneously, .each ,identier starting the .hunt for the calling line in Va different lnumber .group circuit. When one identieriinds the line, Ait identifies the sender which originated `the identification operation, .after `which .all Aof the other identiers are returned to normal.

`ln addition, means is provided :to identify not only the line but the party on that line, yby mea-ns :of a characteristic tone. lMore specifically, means associated with the sleeve terminal `on the :number group frame is used to render the identifier responsive :only to the proper party tone.

According to another :feature of theginvention, the identitier is enabled .to identify Athe .sender `which ds source of the line identifying 'tone by :transmitting la tone back over the sleeve of .theidentiiied line.

These 'and other l features of the invention will bc more clearly understood from fa consideration of ythe lfollowing description, read Ain connection with the drawings, in which:

Figs. 'l and v8 `show three subscribers lines, together withithe `switchesand district junctors over which Aoutgoing calls tare extended;

Fig. 2 shows .in lschematic form ,an .outgoing trunk, a

trunk connector, an associated sender, the tone equipment and the identifier lock-.out circuit;

Fig. 3 shows the marker number group multicontact connector relays;

Figs. 4 and 5 show the identifier :number group Amulticontact connector relays;

Figs. 6, Tand 1l to :1.5 show one .of .a plurality of identiers;

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig. 9 shows one foffa plurality ofnumber group frame circuits;

Fig. l shows in schematic fform azplurality tot markers, identifiers, number groups and connectors; vand Fig. 16 `shows ythe .manner in `which the other ii-gures should be arranged.

This line identifying :arrangement may be used in place of `the "identifier `showzn in Patent 2,629,016 Agranted 'to J. W. Gooderham, February il?, 19'5'3, and reference tmay be made to that patent lfor 'typicalioperating .circuits vfor the 'relays of the trunk l'and sender tof lFig. 2. atypical :6 showing the :twentyablock progress circuit;

7 showing the units identification 'control circuit; ll showing the number group selection circuit; l2 showing 'the hundred-block register relays; 13 showing the detector input Iconnector relays; 14 showing `the detectors and output relays;

l 4showing 'the detector output connector relays;

2,695,928 Patented Nov. 30, 1954 2 cross-bar system Vis shown in Patent 2,235,803 to W. W. Carpenter, March 18, 1941, and reference is made to that dslsue for the operation vof relays of thedistrict junctor o 1g.

Briey, when a calling subscriber initiates a toll call, the line is extended to `a trunk outgoing to the toll oice and an outgoing sender 4is attached tothe trunk to control the apparatus at the distant office and to transmit thereto the Vnumber ofthe called line. This sender also includes a calling line register and a recorder .or ticketer which records the details of `the -call for charging purposes. When the `sender has received the called number, and has determined Whether or not the call was originated by the tip party on the calling line., ,it connects a characteristic tone to the sleeve conductor :of the connection, over which the tone is .extended to a `sleeve terminal individual to the line designation at a number group frame. 1n the case of party lines, a plurality yof terminals are marked.

At the same time a `common start relay lis operated which operates the individual start relays in all of the line identifiers. Each identifier is arranged to start hunting for the identification tone in a diderent number group so that -a minimum time is required to ind the marked terminal.

Each number `group includes a vmaximum of 80.0 number terminals and an .identifier tests the terminals in groups of 160 :so that a maximum of vlive testing operations determines whether the marked terminal is located in a particular number group. if the terminal is within the number group, the identifier registers the thousands, hundreds and tens -vdigit and then proceeds to determine the units digit. By means of the `party characteristic of the tone, the identier is enabled during the units test to determine whether it .has lfound the `terminal .of the correct party.

As soon-.as one identifier has found the marked terminal it determines the sender which originated the marking tone, connects therewith and transfers the designation to that sender. For this purpose it operates a relay in an identifierlock-out chain :and ltransmits a tone of a different frequency back over the tested `sleeve terminal and circuit to the sender, to operate la relay individual to that sender. Under the joint control .of the identifier lock-out relay and the sender relay, econ-hector relay is operated over contacts of which the designation as set up in the identitier is transferred to the calling number register of the sender, after which 4the identier is released.

As soon as the sender has been identied and the sender relay operated, the common rstart relayiis `released and the other identifiers are returned to normal.

Detailed description When the subscriber at ,substation wishes to make a .toll call, -he removes Vhis receiver from the switchhook, thereby initiating ,a series of operations resulting in the connection of his line ywith an idle district junctor such as junctor 107 over jprimary vline switch 103 .and secondary line .switch 104 and with an idle originating sender 123 over ,a sender link 122. He then dials the `number of the wanted line, which .is registered in the originating sender 123. rl`he sender 12,3 connects with an idle originating marker 125 through the marker connector 124 -and transmits -the designation of the wanted .oce yto the mar-ker, whichfunctions toconnect the district junctor 107 through a set Vof switches, represented by vswitches 114 and 115 to a vtrunk .outgoing to fthe toll oice. When lthis connection has `been established, a `circuit is Aclosed from battery through the Aleft .winding of the trunk line relay 201, contact V3: of lrelay `2.00, l.ring conductor 117 of the trunk, through .the switches 115 and 1,14 and sender link 122 to a bridge 1established in the sender and back to tip conductor yi116, contact ni rela,l l200, right winding of relay 201 to ground. Kola-51,201 operates, operating relay 202 which `in r`turn .operates the sta-rt 'relay 203 of the trunk connector 204 `which 4,serves Yto .connect :the trunk with an idle outgoing `sender 2.05,. This sender yincludes a called line number register 206 which senves to control the exten-sioniof the cal-l to the called line, a party identication circuit 207 forindicating when the `tip party of a twoparty line is calling, :a calling .line number 4register 208 anda recorder-or ticketer1209ifor recording lthe 4details of the call for charging purposes.

When the sender has been attached to the trunk, relay 200 is operated to transfer the tip and ring conductors from relay 201 to the sender 205, after which the originating sender 123 transmits the called line designation to the called line number register 206. When the designation has been received, relay 210 operates to start the operation of the line identifiers. The sender proceeds to control the completion of the connection in the appropriate manner.

When the control equipment at the originating ofiice has completed its functions, relays 108 and 109 are operated in the district junctor 107 and the calling line is connected through to the sender 205, where the party identification circuit 207 functions to test whether or not the calling substation is a tip party on a party line. Assuming that the substation 100 is the ring party, the line will not be grounded and relay 211 remains unoperated.

Relay 210, when operated as above described, closes a circuit from battery over its contact 2, normally closed contact of relay 216, contact 2 of relay 213 through the trunk connector 204 to ground through the winding of relay 214. Relay 214 connects ground over its contact 1 to start conductor 250, which is common to all ticketing trunks, to battery through the Winding of the common start relay 1100.

Relay 214 also connects the identification tone to the sleeve conductor of the trunk. Since it has been assumed that a ring party is calling and relay 211 is not operated, the source 251 of 270-cycle alternating-current characteristic of the ring party is connected over contact 2 of relay 211, contact 1 of relay 210, contact 1 of relay 218, to the upper winding of hybrid coil 253. Current is induced in the middle winding of hybrid coil 253 and passes through the trunk connector 204, contact 2 of relay 214, sleeve conductor 118 of the trunk, through switches 115 and 114, contact 3 of relay 109, contact 1 of relay 112, contact 3 of relay 108, resistance 110, through line switches 104 and 103, conductor 119 to cross-connecting terminal 951, individual to the calling line at the number group frame 950.

Common start relay 1100, when operated, connects ground to the individual start relays of all identifiers. At its contact 3, relay 1100 closes an obvious circuit for the start relay 1101 individual to the identifier shown in detail, while at its contacts 1 and 2 relay 1100 connects ground to conductors 1102 and 1103 leading to the individual start relays of identifiers 1000 and 1001. As many identifiers are provided as are required by the traffic.

Relay 1101 closes a circuit from ground over its contact 2, conductor 1104, contact 4 of relay 1105, contact 6 of relay 1106, to battery through the winding of relay 1107 to start the selection of a number group. Relay 1107 operates and closes a circuit from ground on conductor 1104, contact 1 of relay 1108, contact 1 of relay 1107, contact 3 and winding of relay 1106, to battery through resistance 1109. Relay 1106 operates and locks over its contact 4 to ground on conductor 1104. A circuit is closed from battery through resistance 1110, winding of relay 1105 over contact 4 of relay 1106 to ground on conductor 1104, but relay 1105 cannot operate, since ground on conductor 1104 is connected over contact 1 of relay 1108, contact 1 of relay 1107 and contact 1 of relay 1105 to resistance 1110 in shunt of the winding of relay 1105.

With relay 1106 operated, a circuit is closed from ground on conductor 1104, contact 2 of relay 1106, contacts 1 of relays 1112, 1113, 1114 and the intermediate relays to battery, through the winding of relay 1111. Relay 1111 operates in this circuit and locks over its contact 2 and contact 4 of relay 1112 to ground on conductor 1104.

Relays 1111 to 1114 constitute a number group walking or progress circuit. One such relay will be provided for each number group and the relays are operated in succession to determine the order in which the identifier will seize the number groups to hunt for the calling line. A set of cross-connecting terminals 1115 is provided so that each identifier will be arranged to start searching at a different number group frame. Each of the relays 1111 to 1114 closes two circuits leading to the number group lockout, or preference circuit associated with the corresponding number group circuit. With the cross-connections as shown, relay 1111 closes circuits leading to the number group preference circuit shown in detail, while relay 1113 is arranged to close corresponding circuits leading to the number group lock-out circuit 1010 associated with number group 1020. Relay 1114 is arranged to close corresponding circuits leading to number group lock-out circuit 1011 associated with number group 1021.

ln identifiers 1000 and 1001 the cross-connections such as 1115, would be so arranged that different number groups would be the first to be seized, for example identifier 1000 would search first in number group 1020 and identifier 1001 would search first in number group 1021.

The number group lock-out or preference circuit shown in Figs. 3, 4 and 5 includes one preference relay such as relays 301 and 311 for each marker and one preference relay such as relays 401, 411 and 501 for each identifier and a gate relay 420. Whenever an identifier is attempting to search in this number group, the gate relay 420 is operated as will be described. Assuming that no other identifier has seized the number group shown in detail, relay 420 will be normal and ground will be connected to ctnductors 421, 422 and 423 leading to the three identi ers.

Ground on conductor 423 completes a circuit over contact 5 of relay 1111, contact 6 of relay 1105, upper winding of relay 1116 to battery. Relay 1116 operates in this circuit and closes a locking circuit for itself from battery, through its lower winding, and over its contact 3, contact 3 of relay 1108 to ground on conductor 1104. The operation of relay 1106 opens the operating circuit of relay 1107, but that relay is slow to release and the operation of relay 1116, at its contact 1, closes a holding circuit for relay 1107 to conductor 1104 to hold it operated.

With relay 1116 operated, a circuit is closed for identifier preference relay 501, which may be traced from battery through the winding of relay S01, conductor 502, contact 5 of relay 420, conductor 424, contact 6 of relay 1111, contact 7 of relay 1106, contact 2 of relay 1116, contact 3 of relay 1108 to ground on conductor 1104. Relay 501 operates in this circuit and locks over its contacts 3 and 5 to conductor 424 and its operating circuit, independent of gate relay 420. At its contact 5, relay 501 extends conductor 424 to the winding of relay 420, operating the latter relay.

Relay 501 represents the first preference for the number group of Fig. 9 and, when operated, opens the locking circuit of lower preference relays, in the possible event that any such relay operates at the same time. Relay 420 in operating, disconnects ground from conductors 421, 422 and 423 to indicate that the number group is associated with an identifier and also opens the operating circuits of the identifier preference relays to release operated lower preference relays and prevent their operation while the number group and identifier are associated.

In order to prevent a marker and identifier connecting with a number group at the same time, the circuit for operating the multicontact relay to make this connection is carried over contacts of the marker preference relays. Assuming that no marker is attempting to seize the number group, a circuit may be traced from ground over contact 1 of marker preference relay 301, similar contacts of intermediate marker preference relays, contact 1 of marker preference relay 311, conductor 330, contact 2 of relay 501 to battery through the winding of multicontact relay 500.

Since the marker uses the number group for only a brief interval, this arrangement permits the marker to disconnect the identifier for long enough to get the information required. Since the identifier preference relay is locked, as soon as the marker disconnects, the identifier may reoperate its multicontact relay and proceed.

With relay 500 operated to connect the identifier with the number group, a circuit is closed from ground over contact 5 of relay 500, conductor 503, to battery through the winding of relay 1117. Relay 1117 operates in this circuit and closes a circuit from ground on conductor 1104, contact 4 of relay 1116, conductor 1118, contact 2 of relay 1117, conductor 1119, contacts 8 of the eight hundred-block relays 1207 to 1200, conductor 1208, contact 2 of relay 700 to battery through the winding of relay 701. Relay 701 operates and locks over its contact 3, contact 1 of relay 715, conductor 1118, contact 4 of relay 1116 to ground on conductor 1104.

Relay 701 at its contact 5 connects ground to conductor 702 and thence over the normally closed contacts 5 of relays 1200 to 1207 to battery through the winding of relay 1209. Ground on conductor 702 also extends over contact 1 of relay 1209 to the winding of relay 1210, but the operation of relay 1209 immediately opens this circuit, preventing the eiiective operation .of relay 1210 at this time.

`W`ith relay 1209 operated., ground on conductor 702 is extended over contact 2 of relay 1209, normally .closed contacts 1, 3 and the intermediate back contacts of relay 12110, conductors 1220 :to 1227, contacts 16, 17 and the intermediate contacts of the identiiier connector relay 500, conductors 520 to 527, through .cable 5-9A to battery through the windings of hundred`block relays 900 to 907 in the number group circuit, operating all of these relays.

Relay 701 also closes Va circuit from ground, connected as above traced to conductor 1118, over contact 1 of relay 703, contact 4 of relay 701, conductor 704, in parallel to battery through the windings of relays 13.00 and 1500. In addition, relay 701 connects ground over its contact 1, conductor 705, contact 3 Aof relay 605, contact 7 of relay 604, contact 9 of relay 603, contact 9 lof relay 602, contact 9 of relay 601 to battery ythrough the lower winding of the first twenty-block progress relay A600.

Relay 600 closes a `circuit from ground at contact 4- of relay 606, Contact 3 of relay 600, conductor `610, contact 14 of connector relay 500, conductor 530 through cable 5-9A to the number group circuit and over the contacts 1 of the operated hundred-block relays to battery through the windings of the rst twenty-block relay associated with each hundred-block relay. Relay =910 is operated over contact 1 of relay 900 and relay 920 over contact 1 of relay 907.

With relays 910 and 920 operated, the sleeve punchings of 1160 lines are tested for the identifylng tone. Each punching is connected through to an indlvidual resistance and the resistances of each twenty-block are multipled into two groups of ten each, according to whether the corresponding tens digit is odd or even. The sixteen groups of resistances are connected tho the left or input windings of sixteen repeating colls as Shown in Fig. l2. l

Specifically, terminal 951, to which identifying tone was connected as above described, is connected over conductor 952, Contact 1 of relay 910, conductor 930, contact 4 of relay 500, conductor 540 to resistance 1230 and through the left winding of repeating coil 1240 to ground.

When relay 1300 was operated, as above described, the right windings of coils 1240, 124-1, etc., were connected to the input windings of the detectors of Fig. 14. Relay 1500, which operated in parallel with relay 1300 connects the output circuits from the detectors to the windings of the hundred-block register relays 1200 to 1207 When relay 1116 was operated as above described, in response to the operation of the number group selectlng relay 1111, it closed a circuit from ground on conductor 1104, contact 4 of relay 1116, conductor 1118, contact 1 of relay 1117, conductor 1120 to battery through the winding of relay 1504. When relay 1117 operateslln response to the operation of the identliier connectlng relay 500, this circuit is opened and relay 1504 releases closing a circuit from ground on conductor 1118 over its contact 1 to battery through the windlng of relay 150,5. Relay 1505 initiates a timing interval to permit the identiier circuits to be established. For thls purpose, relay 1505, at its contact 5v disconnects ground from in shunt of condenser 1506, and at its Contact 3 connects +130 volt battery through resistances 1507 and 1508 to condenser 1506 to cause the condenser to charge. Condenser 1506 is connected through resistance 1508 to the control anode 1509 of tube 1510. Cathode 1511 of tube 1510 is connected to ground over contact 3 of relay 1514 and contact 6 of relay 1505, while the main anode 1512 of tube 1510 is connected through the winding of relay 1513 to +130 volt battery over contact 3 of relay 1505. When the charge on condenser 1506 reaches the breakdown voltage of tube 1510 the tube becomes conducting and relay 1513 operates across the tube.

With relay 1513 operated, a circuit is closed from ground over contact 6 of relay 1505, contact of relay 1513 to battery through the winding of relay 1514. Relay 1514 operates in this circuit and locks over its contact 4 to ground over contact 6 of relay 1505. At its contact 3, `relay 1514 removes ground from anode 1511 of tube 1510, quenching the tube and releasing relay 1513. At its contact 1, relay 1514 .connects battery to conductor 1515 which extends in multiple to the normal contacts .of relays 1420 .to 1435 preparing circuits through the windings of the latter relays.

Since tone from terminal 951 flows through the left winding of repeating coil 124.0, current, induced in the right winding of that coil, Hows over Vconductors 1260 and 1261, contacts 3 and 4 Aof rela-y 1300, conductors 1316 and 1317 to detector 1400, resulting in the operation of polarized relay 1438 which connects ground to the winding of relay 1420. Relay 1420 therefore operates and locks over its contact 7 to battery.

If more than one line were marked in the group of lines being tested, the associated detector rel-ay andv output relay would operate, and, due to the sequence wiring of the contacts, the higher numbered relay would have the preference.

Assuming that relay 1420 is operated alone, it closes a circuit from battery over contact 9 of lrelay 1500, contact 2 of relay 1501, conductor 1503, con-tact 8 of relay 1435, contacts 10 of relays 1428, 1-427 and intermediate relays, contact 8 Iof relay 1420, 4conductor 1439, contact 3 of relay 1500, conductor 1516 to ground through the upper winding of hundred-block relay 1200.

In addition, relay 1420 closes a `circuit from ground atcontact 1 of relay 1303, conductor 1304, contact 2 `of relay 1500, conductor 1517, contact 2 of relay v1435, contact-s 3 of relays 1428, 1427 and intermediate relays, Contact 3 of relay 1420, conductor 1437, contact 1 of relay 1300, conductor 1305, to battery through the lower winding of relay 1212. The operation of relays 1200 and 1212 indicates that the l'ine lies in the tirst or zero hundred group and in the tens subgroup having an even tens digit.

With relays 1212 and 1200 operated a locking circuit is closed from ground over Contact 1 of relay 1211, vupper winding and contact 1 of relay 1211, lower winding and contact 7 of relay 1200, conductor 1213, contactl 2 of relay 701, to battery through the winding `of relay 700. Relay 700 operates in this circuit, closing an obvious circuit for relay 703. Relay 703 operates and locks over its Contact 3 to ground at contact 5 of relay 701. Relay 703 at its cont-act 1 disconnects ground from conductor 704, releasing relays 1300 and 1500, disconnecting the detectors from the input and output circuits causing relay 1438, relay 1420 and any other relays of the group 1420 to 1435 to release.

Relay 703 closes a circuit from battery through lthe winding of relay 1504, contact 2 of relay 1505, conductor 1528, contacts 1 of the units register relays 730, 735, 738 and the intermediate relays, contact 1 of relay 713, contact 2 of relay 703 to ground on conductor 1118. Relay 1504 operates in this circuit, opening the circuit of relay 1505. Relay 1504 locks over its Contact 2 and contact 4 of relay 1505 to ground. When relay 1505, which is slow to release, opens its front contacts, the operating and locking .circuits of 1relay 1504 are both opened and relay 1504 also reeases.

With relay 1505 released, a circuit is closed from battery through the winding of relay 711, conductor 716, contact 1 of relay 1505, conductor 1528 and thence as above traced to ground on conductor 1118. Relay 711 operates and locks over its contact 2, contact 1 of relay 713, contact 2 of relay 703 to ground on conductor 1118. Relay 711 closes a circuit from ground over contact 1v of relay 712, contact 3 of relay '711, conductor 717, in parallel through the windings of relays 1307 and 1529 to battery. Relays 1307 and 1529 prepare the circuits by which the detectors identity the individual line, relay 1307 connecting the sleeve leads of the group of the lines in which the signal was detected during the previous identication step to separate detectors in order that the particular one of the ten lines may now be singled out .as the line on which the signal appears.

When relay 1212 operates as previously described, it closes an obvious circuit for operating relay 1214. The identiiier connector relay 500 connects ground to twenty conductors 550 to 569 which extend through cable 5-9A to contacts on the twenty-block relays 910, 914, etc.

As soon as identifier hundred-block relay 1200 operated as above described, it opened the circuit of relay 1209, causing that relay to release and extend ground onl conductor 702 to the winding of relay 1210. Relay 1210 opens the previously traced multipled operating circuits for the hundred-block relays 900 to 907 of the number group and connects these circuits individually to contacts of relays 1200 to 1207. With relay 1200 operated, the operating circuit of relay 900, extending as above traced to conductor 1220, is further extended over contact 2 of relay 1210, contact 6 of relay 1200, to ground on conductor 702. Therefore, relay 900 is reoperated, in turn reoperating the twenty-block relay 910.

Conductors 550 to 569 are extended over contacts 11 and 12 and intermediate contacts of relay 910 to terminals 953, 954, etc., on frame 950, these terminals being associated with the twenty sleeve terminals of the twenty lines having the twenty directory numbers determined by hundred-block relay 900 and twentylock relay 910. Terminals like terminals 953, 954, etc., are useful for indicat- 2 ing whether the number belongs to a tip party, a ring party (or individual line) or a P. B. X line and for that purpose are cross-connected to terminals on rack 957, there being a row of terminals on rack 957 for each such class of line.

Substation 100 is assumed to be the ring party on the line and therefore terminal 953, associated with sleeve terminal 951 individual to substation 100, is cross-connected to terminal 955 in the row of terminals on frame 957 characterizing the ring party. Terminal 955 is conby relay 500. The ring party relays are also operated for individual lines and P. B. X lines. Relays 1308, 1309, etc., connect the sleeve terminals of the associated lines to band-pass filters tuned to the characteristic ring party frequency of 270 cycles which are connected to the first ten detectors, while relays 1310, 1311, etc., connect the associated sleeve terminals to filters tuned to the characteristic tip party frequency of 330 cycles. Therefore, the detectors respond only if the frequency applied to the sleeve terminals is that indicated by the cross-connections on the number group frame.

Sleeve terminal 951, to which 270-cycle current was connected as described, is connected over conductor 952, contact 1 of relay 910, conductor 930 through cable 5-9A, contact 4 of relay 500, conductor 540, contact 1 of relay 1207, contact 7 of relay 1214, conductor 1216, ,1.,

condenser 1314, resistance 1315, contact 1 of relay 1307, Contact 1 of relay 1309 to 270-cycle filter 1313 which is connected over conductors 1316 and 1317 to detector 1400. Therefore, relay 1438 operates to supply ground to the winding of relay 1420.

When relay 1504 releases as above described, relay 1505 reoperates to initiate the operation of the test timing circuit. When relay 1514 operates in response to this timing operation, it connects battery over its contact 1 to the windings of relays 1420 to 1435 as previously described and relay 1420 operates and locks to battery over its contact 7.

With relay 1420 operated, a circuit is closed from battery over contact 7 of relay 1529, contact 2 of relay 1502, conductor 1503, contact 8 of relay 1435, contacts 10 of relays 1428, 1427 and the intermediate relays, contact 8 of relay 1420, conductor 1439, contact 1 of relay 1529, conductor 1530 to ground through the upper winding of relay 1318 and to ground through the left winding of relay 730. Relays 1318 and 730 operate and lock in a circuit from ground through the lower winding and over contact 3 of relay 1318, conductor 1319, right winding and contact 4 of relay 730, contact 1 of relay 711, to battery through the winding of relay 710. Relay 730 registers the units digit of the line designation and with relay 710, closes a circuit from battery through the winding of relay 712, contact of relay 710, contact 2 of relay 730, contacts 1 of relays 735, 739 and the intermediate relays, contact 1 of relay 713, contact 2 of relay 703 to ground on conductor 1118. Relay 712 operates and locks under the control of relay 711.

The identification process is now complete. Relays 730 to 739 contain the units digit, relays 600 to 604 in combination with relays 1211 and 1212 contain the tens digit, while relays 900 to 907 in the number group are wired el (i to supply the hundreds and thousands digits, which are transmitted over the conductors of cable 5-9B, contacts of relay 500, contacts of relay 1210 and the conductors of cable 12-15 to the registers indicated at 1531.

With relay 712 operated a circuit is closed from ground on conductor 1118, contact 3 of relay 712, contact 6 of relay 730, conductor 718 to battery through the winding of relay 1532 to prepare for the transfer of the line designation to a recorder.

A circuit also extends from ground, connected to conductor 718 as above traced, contact 1 of relay 1121 to battery through the winding of relay 1122. Relay 1122 operates to indicate that a number has been identified and at its contact 2 closes a locking circuit for start relay 1101 independent of the common start relay 1100. At its contact 4, relay 1122 connects ground to conductor 1120 to operate relay 1504 and disable the timing circuits. in addition it closes a circuit for initiating the connection of the identifier with the sender at which the identifying tone originated. This circuit may be traced from battery through resistance 1123, contact 2 of relay 1124, contact 3 of relay 1122, conductor 1125 through cable 2-11 to ground through the winding of relay 220, individual to this identifier in the identifier lock-out chain of Fig. 2.

This identifier lock-out chain including relays 220, 221 and 222, each individual to an identifier, permits only one identifier to search for a sender at a time. Relay 220, being the first relay of the chain can operate but, if some other identifier has already seized the lock-out chain, relay 220 does not become effective until the lock-out relay of the other identifier is released.

With relay 220 operated alone, a circuit is closed from 100G-cycle current, through resistance 223, contact 1 of relay 222, contact 1 of relay 221 and the corresponding contacts of intermediate relays of the chain, contact 1 of relay 220, conductor 224 through cable 2-11 to the identifier, contact 1 of relay 1122, conductor 1126 to ground through the right winding of repeating coil 1320. This tone is repeated into a circuit which may be traced 'from ground over contact 2 of relay 1307, contact 2 of relay 1318, left winding of repeating coil 1320, and thence, over the circuit used in identifying the line, over contact 1 of relay 1318, contact 1 of relay 1307, resistance 1315, condenser 1314, conductor 1216, contact 7 of relay 1214, contact 1 of relay 1200, conductor 540, contact 4 of relay 500, conductor 930, contact 1 of relay 910, conductor 952, terminal 951, conductor 119, over the sleeve contact of the line which has been identified, through switches 103 and 104, resistance 110, contact 3 of relay 108, contact 1 of relay 112, contact 3 of relay 109, switches 114 and 115, conductor 118, contact 2 of relay 214, through the trunk connector 204, middle winding of hybrid coil 253 in the sender 205 to ground. This 100G-cycle current is transmitted through the lower winding of hybrid coil 253, 100G-cycle filter 225, amplifier 226 and rectifier 227 to the winding of relay 217, operating that relay.

Relay 217 closes a circuit from battery over its contact to ground through the winding of relay 218. Relay 218 operates and locks over its contact 3, contact of relay 216, to battery over Contact 2 of relay 210. At its contact 1, relay 218 disconnects the identifying tone from the hybrid coil and at its contact 2 opens the circuit of relay 214, thereby opening the circuit of the common start relay 1100. If no other line is awaiting identification, relay 1100 releases, in turn releasing the start relays of the other identifiers and restoring them to normal.

Relay 217 also closes a circuit from battery over its contact, contact 1 of relay 228, to ground through the winding of relay 229 individual to this sender. With relays 220 and 229 operated, a circuit is closed. from battery over contact 5 of relay 222, contact 6 of relay 221 and similar contacts of intermediate chain relays, contact 4 of relay 220, contact 3 of relay 229, winding of relay 230 to ground. Relay 230 serves to connect sender 205 with the identifier shown in detail. Relay 230 extends its operating battery over its contact 2 to ground through the winding of relay 228. Relay 228 operates and locks over its contact 2, contact 3 of relay 218, contact of relay 216 to battery at the contact of relay 210 and at its contact 1 opens the circuit of relay 229.

Relay 230 also connects ground over its contact 1, conductor 233 through cable 2-11 to battery through the winding of relay 1124. Relay 1124 operates to indicate that the sender has been found and locks through the winding of rela-y 1121 to) ground on conductor 1110 but relay 1121 does not operate, beingI shunt'ed bythe operatln-g circuit of relay 1124/. At its' contact 2',v relay 1124 disconnects battery from the winding' of rela-y 220, releaslng relay 220 and permitting other identifiers tov enter the lock-out circuit. With relay 220 released', the 100G-cycle current is disconnected and relay 217 releases.

With relay 230 operated, the' line designation is set up on the cal-ling line number register 208- of the sender, the plurality of circuits forv so doing being indicatedi by circuits closed? over contactsl 3 and 4 of relay 230, and conductors 234 andi 235 through cable 2li-'17. A set of ten circuits isprovided for each ot the fou-r digits, one conductor of eachy set being grounded bythe identifier'. Relay 1532 connects the four' sets of: conductors through to the identifier,- the two sets of conductors representing the thousands and hundreds digits being marked by the register 1531, which was operated from lthe hundredlblock relay of the number group as previously described. The tensdigit conductors are marked over contacts of the twenty-block progress relay 600 to 6041 and of the odd and even tens relays 1211 and 1212. Since it was assumed that rela-ys 1212 and 600 were operated, ground is connected over Contact 3 of" relay 1212, conductor 1217, contact 1 of rel-ay 600, conductor 620', contact 3 of relay 1532 to conductor 1533'. The units. digit conductors are grounded over contacts of the units relays 730 t'o 739. Since relay 730 wasg assumed tobe operated, ground on conductor 1111-8 is extended over contact 3 of relay 730, conductor 720, contact 1 of relay 1532 to conductor 235.

When the registration has been completed, relay 216 is operated in the sender, releasing relays 218i, 228` and 230, disconnecting the identifier frornthe sender. With relay 230i released?, ground i's removed from conductor 233, permitting relayy 1121 to` operate in the locking circuit of relay 1124. Relay 1121 at its contact 1 opens the circuit of relay 1122 and that relay releases. The release of relay 11221op'ens the locking circuit' of rel-ayl 1101 which also releases, removing ground from conductor 1104 and thereby trom conductor 1118 to'A restore the identi-fier to normal.

However, it other calls aire awaiting identification, the common start relay 1100 isheld operated and in turn holds relay 1101! operated which holds relay 11251v operated. ln' that case, the release of relay 1122 closes a `circuit from ground on conductor 1104, contact of relay 1122, contact 2 of relay 1121, toA battery through the wind-ing of relay 151081 Relay 1-1'08` operatesl in this circuit and at its contact 3 opensthe locking circuit of? relay 1116- causing that relay tol release and disconnect ground from conductor 1118, thereby releasing relays 1124 and 1121. At its contact 1, relay 1'108 opens the' shunt around the winding of relay 1105, permitting that relay to operate. The operation of relay 11105 opens the circuit of relay 1107 which releases slowly. Relay 1108 closes a*- tem'porary locking circuit for itself over contact 2 oi relay 1107 and contact 2 of relay 1108 to ground on conductor 1104, to insure that relay 1107' release. When relay 1107 has released, relay 1108 releases.

Since relays 1105 and 1106 are now both operated, a circuit is closedl for reoperating relay 1107 from battery through the' winding of that relay over Contact 5 of relay 1106 and contact 3' of relay 1105 to= ground on conductor 11041. With relay 11107 opera-ted and rel-ay 1108j released, ground on conductor 11504' isconnected' over Contact 1 of relay 1108, contact 1 of relay 1107, contact 2 of relay 1105 to battery through resistance 1109 i-nshunt of the winding of relay 1106-, causing the latter relay to release. Relay 1105 is held operated over the normal Contact 3 of relay 1106, Contact 1 of relay 1107, contact 1 of relay 1108l to ground on conductor 1104.

With rela-y 1106 released.y a circuit isV closed from ground on conductor 1104, contact 1 of relay 1106, contact 1 of relay 1111 to battery' through the winding ofl the next number group select relay 1112. Relay 1112 operates and locks over its contact 3 and Contact 4 of the next relay of the' chain to ground on conductor 1104. At its Contact 4 relay 1112 opens the locking circuit of rela-y 1111 causing the latter relay to release.

With relay 1105` and relay 1112 operated.. the circuit of relay 1116 is extended to the conductor,= corresponding to conductor- 423.1cading to the next number group pref- @rence circuit. lf that circuitis available, the gate relay will' be normal and relay 1116 operates... after which the [est proceeds astorl the rs't number group. If some other identifier is hun-ting in this number group, the gate relay will' be operated and relay 1116 will fail to= operate, Therefore, after an interval, relay 1107 will release and open the holding circuit of rela-y 1105. With' relays 1105 and 1106 both released, relay 1107 reoperates, reoperating relay 1106 to opera-te the next number group select relay. In this manner, an identifier is enabled to skip number group" circuits which are bci-ng used by other identifiers.

lf the identified line had not been found among the first group of lines tested', none of the relays 1420 to 1435 would have been operated and relays 1300! and 1500 remain operated. l'n this case, the operation of relay 1514 connects 130 volt battery over its contact 2 to' the' Winding of relay 1510 and through resista-frees 1519 and 15220 to condenser 1.521. With relay 1505 operated, ground is removed from in shunt ofl condenser 1521 so that the condenser now charges.

Condenser 1521 is connected through resista-nce 1520lto the control anode 1523 or"- tube 1522, relay 1518 is connected to the main anode of tube 1522 and ground is connected over con-tact 6 of relay 1505 anfl Contact' 2 of relay 1526 to the cathode of tube 1522 When condenser 1521 receives a sufficient charge, tube 1522' becomes conducting andl relay 1518 operates, in turn operating relay 1526` which locks over its Contact 3 to ground at contact 6 of relay 13505.

Therefore, if no line is found in the rst group tested, relay 1526 operates after a measured additional interval, closing a circuit from ground over its contact 1, conductor 1527, contact 11 of relay 1300, conductor 1306l to battery through the Winding of relay 606. Relay 606, at its` contact 1, connects ground to conductor 1120, opera-ting relay 1504 which locks over its Contact 2 under the control of relay 1505 and at its contact 1 opens the circuit of rela-y 11505 which releases slowly. With relay 1505 released the timing circuits are restored to normal- In addition, relay 606 at its contact 4 opens the circuit of the twenty-block relays 910, 920-, etc.- inA the number group and at its contact 2 connects ground over con-tact 1 of relay 60S, contact 6 of relay 600` to battery through the lower winding of relay 601. Relay 601 operates and locks over its contact 8, contacts 9 of relays 602 and 603, contact 7 of relay 604, contact 3 of relay 605, conductor 705 to ground at contact 1 of relay 701'. Relay 601 opens the operating circuit of relay 600, but that relay is held operated. in a circuit from battery throughits upper winding and contact 5, contact 5- of relay 605 to ground at contact 3 of relay 606.

When relay 1505 releases, in turn releasing relay 1526, relay 606 is also released in turn releasing relay 600. With relay 606 released, ground is connected over contact 4 of relay 606 and contact 3` of relay 601 to cond-uctor 611 to.` operate ther neXt set ofv twenty-block relays and bring about the test of the second group of lines. If the identified line does not appear in the second group, re lay 606 is again operated under the control of timing tube 1522 and the test thus progresses until all of the lines' in the nlunber group have been 'tested for the presence of identifying tone.

If no identifying tone has been detected, when relay 606 operates, following the operation of the last twentyblock selecting' relay 604 and the release of relay 603, a circuit isy closedI from ground over contact 2 of relay 606, Contact 1 ofy relay 605, contact 7 of relay 600', contacts 11 of relays 601, 602 and 603, conductor 615 to battery through the winding of relay 1108. Relay 1108 functions' as above described to cause the identifier to hunt for the line in the next number group.

Since thev two parties on a party line will have different directory numbers, the sleeve contact of the party line is connected to two terminals on number group frames. The two parties are distinguished for identification by means of the party identication circuit 207 of the sender, where relay 211 is operated when a tip party is calling and is normal for' the ring party and for all other lines. As above described, with relay 211 normal the identification tone is one of 270` cycles supplied by source 251. If al tip party is calling and relay 211 is operated, the identificationI tone is supplied from source 254 having a frequency of 330 cycles. During the twenty-block test no discrimination is made between the two frequencies, and it is therefore possible that the identifier may identify the twenty-block including the non-calling partys terminal'. l

Therefore, when the units test is made, the frequency 

